I usually take Resveracel from Thorne Research, which is a very neat stack. It contains low-dose resveratrol, nicotinamide riboside, quercetin and betaine.

For a higher resveratrol dosage I like Biotivia. Of course these are expensive supps but IMHO they are worth it. I combine a low dose of them with red wine intake (I am lucky to manufacture my own red wine ^^).